Both the federal and Newfoundland and Labrador governments are finding ammunition in an independent economic review of the new equalization formula.

Premier Danny Williams launched a nation-wide series of attack ads against Prime Minister Stephen Harper, accusing Harper of breaking a 2006 campaign promise to exclude offshore oil revenues from the equalization formula.

Williams has claimed the new formula could cost Newfoundland and Labrador hundreds of millions of dollars per year, once the Atlantic Accord expires.

However, Memorial University economist Wade Locke unveiled an analysis earlier this week that showed Newfoundland and Labrador could receive $5.6 billion more under the new formula, compared to the status quo.

Locke refused to take sides in the dispute, which was ratcheted up this week with federal government newspaper and radio ads that say Williams has used factually inaccurate information.

Fisheries Minister Loyola Hearn, Newfoundland and Labrador's federal cabinet representative, lauded Locke's findings.

"An unbiased report from a reputable, local, independent economist has more credibility than if each level of government had produced its own figures and attempted to duke it out," Hearn said in a statement.

The Newfoundland and Labrador government, though, says Locke's analysis bolsters Williams's campaign.

The new formula includes 50 per cent of non-renewable resources. Williams has called on Harper to stick with his original promise of a system that contained no cap on benefits, and which excludes non-renewable revenues altogether.

Locke found that that proposal was the most lucrative of all options, with the Newfoundland and Labrador treasury receiving about $28.6 billion over the next 12 years.

"The shortfall is about $4.5 billion over 13 years.… What we've received is less than what we were promised," said provincial Finance Minister Tom Marshall.

"I would say to the federal government that you gave us a commitment. Honour it."